SM5956A NPC, SM5956A Datasheet - Page 21

• Manufacturer Part Number: SM5956A
• Description: 6-channel Asynchronous Sample Rate Converter
• Manufacturer: NPC

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Group Propagation Delay
t
t
Cratio
t
t
Response Time
A certain amount of time is required to calculate the sample rate conversion ratio in the conversion rate detec-
tor. Assuming as a prerequisite that the SM5956A is supplied with a stable input-system sampling frequency
(fsi: input on LRCI) and a stable output-system sampling frequency (fso: derived from the SCK clock), the
time required after system reset to determine the sample rate conversion ratio with 16-bit precision is defined as
the minimum response time, given by:
Response time = 28140/fso (638ms at fso = 44.1kHz)
INPUT
OUTPUT
OUTPUT
OUTPUT
Input frequency
fsi [kHz]
44.1
44.1
44.1
− t
− t
32
32
48
48
32
48
: Serial input data (fsi rate) read end timing (LRCI clock rising edge)
: Serial output data (fso rate) output start timing (LRCO clock rising edge)
: Sample rate conversion ratio (fsi/fso)
INPUT
INPUT
Data waveform image
Serial data input
= ((51.791 × Cratio + 41.557) ± 36)/fso (at SCKSLN = H, 768fso operation)
= ((51.122 × Cratio + 38.647) ± 36)/fso (at SCKSLN = L, 512fso operation)
1/fsi
1/fso
Output frequency
t
t
INPUT
INPUT
fso [kHz]
44.1
44.1
44.1
48
32
48
32
32
48
SCKSLN = L
t
t
OUTPUT
OUTPUT
SM5956A
594
557
822
473
799
478
447
325
298
−
−
t
t
INPUT
INPUT
Response time [ms]
SCKSLN = H
285
263
406
228
403
302
395
287
264
t
t
OUTPUT
OUTPUT
SEIKO NPC CORPORATION —21
Serial data output